MOSCOW and NEW YORK — Russia is bracing for further unrest as the rouble on Friday slid to a new low against the euro after a succession of moves to devalue its currency. A cut on Friday extended six weeks of devaluations by Russia’s central bank designed to offset the impact of the global economic crisis and falling oil prices as the country’s main export commodity approached its lowest level since 2004. Mikhail Gorbachev, the former Soviet leader, warned Russia faced ‘unprecedentedly difficult and dangerous circumstances and could be ‘heading into a black hole. ‘It is not clear what the fate of our rouble will be or if society has sufficient financial and moral resources, he said. After the depreciation, which was the eighth so far this month, the rouble declined as much as 1.2 per cent to Rbs29.06 versus the dollar on Friday, a four year low. The rouble has now lost nearly 20 per cent of its value against the US currency since August. Analysts at Barclays Capital said the best case scenario would see Russian policymakers, facing the mounting evidence of a recession, allowing a one-off depreciation of 10 per cent or more. […]